Lead

ABSTRACT

A lead for transmitting an electrical signal within a gas turbine engine, from a node at a first part of the gas turbine engine having a first surface to a second part of the gas turbine engine having a second surface, wherein the first part and the second part are coupled at a compressed joint, wherein the lead comprises: a node on the first surface of the first part; a first interconnect, adhered to the first surface of the first part; and a second interconnect, adhered to the second surface of the second part, wherein the first interconnect and the second interconnect abut at the compressed joint to provide, by their contact, a continuous electrical connection from the node to the second part.

Embodiments of the present invention relate to a lead. In particular,they relate to a lead within a gas turbine engine.

Gas turbine engines are commonly used as aero-engines for aero planes.Each model of an engine is tested to ensure that the parameters of theengine (temperature for example) do not exceed designated thresholdvalues.

During testing, the parameters of the engine must be measured andtransmitted to an operator external to the engine. The measured signalmay, for example, be transmitted electromagnetically (using radio waveradiation for example) via a transmitter to an operator. This is notpossible, however, in high temperature regions of an aero engine wherethe transmitter would be destroyed by the high temperatures. Thereforethe measured signal is transmitted through a wire from the hightemperature region to a transmitter in a cooler region (the compressorstage\stages for example). Holes have to be drilled through which tolead the wires. The holes however, shorten the life of the enginesignificantly and may alter its performance during testing.Additionally, the wires are fixed to the engine by plates to preventdisplacement during operation of the engine. The plates are micro-spotwelded to the engine. Cracks are often formed through micro-spot weldingand shorten the life of an engine. As a result, engines have to bededicated to testing. This is expensive and an inefficient use of humanand manufacturing resources.

It is therefore desirable to provide an improved way of leading outsignals from within engines that does not significantly damage theengine or shorten its life.

According to the present invention there is provided a lead fortransmitting an electrical signal within a gas turbine engine, from anode at a first part of the gas turbine engine having a first surface toa second part of the gas turbine engine having a second surface, whereinthe first part and the second part are coupled at a compressed joint,wherein the lead comprises: a node on the first surface of the firstpart; a first interconnect, adhered to the first surface of the firstpart; a second interconnect, adhered to the second surface of the secondpart, wherein the first interconnect and the second interconnect abut atthe compressed joint to provide, by their contact, a continuouselectrical connection from the node to the second part.

Consequently, embodiments of the invention provide an improved way ofleading out signals from within the engine that does not significantlydamage the engine or shorten its life. The engine may be entered intoservice during or after testing. This removes the need for dedicatedengine builds and reduces manufacturing costs of a gas turbine enginemodel.

The first and second interconnects may be thin film interconnects. Thestructure, materials and characteristics of thin film are well known andmay be found in U.S. Pat. Nos. 5,474,619; 6,037,645; 4,185,496;4,221,649; 4,969,956; 5,215,597; 5,979,243; 4,104,605; 4,577,976 and4,722,609. The thin film interconnects may have a thickness of less than0.1 mm and may have a typical thickness in the order of micrometers.Thin film interconnects may be adhered to a surface of the gas turbineengine by a process such as painting, lacquering or photolithography.Thin film interconnects provide the benefit that they allow anelectrical signal to be lead-out through a compressed joint. Thisremoves the need for drilling holes through which to lead out theelectrical signal. Since the thin film interconnect is adhered to thesurface of the engine, it removes the usage of plates and micro-spotwelding. Therefore, the use of thin film interconnects does littledamage to an engine and has little effect on the performance of theengine during testing. If the thin film interconnects are expelled fromthe engine due to wear, they cause little to no damage to the engine.

The compressed joint may be an already existing compressed joint withinthe gas turbine engine. For example, the compressed joint may be acompressed joint between two portions of an interconnecting shaft. Thecompressed joint may be stationary or rotating. The first part may berotating relative to the second part. The second part may be rotatingrelative to the first part. The first part and the second part may berotating but are stationary relative to one another. Therefore, anelectrical signal can be lead out through rotating parts.

The first part of the engine may have a greater temperature than thesecond part of the engine. The first part may be a high temperatureregion and may have an operational temperature in the range 200° C. to800° C. The second part may be a low temperature region and may have anoperating temperature in the range of “ambient temperature” to 750° C.An example of a high temperature region of a gas turbine engine is theturbine stage(s). An example of a low temperature region of a gasturbine is the compressor stage(s). Therefore the abutment of the firstand second interconnects provides the benefit of a continuous electricalconnection between a high temperature region and a low temperatureregion. This allows the transmission of an electrical signal from a hightemperature region to an operator external to the gas turbine engine,via the low temperature region.

A spool within a gas turbine engine may include a turbine stage(s), acompressor stage(s) and an interconnecting shaft.

The thin film interconnects may comprise gold or platinum or any othersuitable material. Gold and platinum are suitable materials for adheringto an engine because they cause very little corrosive damage to theengine.

Thin film interconnects may be run at any angle and connected at anycompressed joint within a gas turbine engine. They may be run througheither the inside or the outside of an interconnecting shaft. Thisallows for the most economic route to be chosen through the engine. Theymay be installed during initial post-manufacture testing or at an engineoverhaul. Additionally, engines do not need to be designed to take thethin film interconnects into account.

For a better understanding of the present invention reference will nowbe made by way of example only to the accompanying drawings in which:

FIG. 1 illustrates a sectional side view of a gas turbine engine;

FIG. 2A illustrates a side view schematic diagram of a lead according toone embodiment of the present invention;

FIG. 2B illustrates a plan view of the schematic diagram in FIG. 2A;

FIG. 3 illustrates a sectional side view of a gas turbine engineaccording to one embodiment of the present invention.

FIG. 4 illustrates a cross sectional view, at a compressed joint, of aninterconnecting shaft of a gas turbine engine.

The figures illustrate a lead 21 for transmitting an electrical signal27 within a gas turbine engine 10, from a node 22 at a first part 24 ofthe gas turbine engine 10 having a first surface 30 to a second part 28of the gas turbine engine 10 having a second surface 32, wherein thefirst part 24 and the second part 28 are coupled at a compressed joint29, wherein the lead 21 comprises: a node 22 on the first surface 30 ofthe first part 24; a first interconnect 23, adhered to the first surface30 of the first part 24; a second interconnect 25, adhered to the secondsurface 32 of the second part 28, wherein the first interconnect 23 andthe second interconnect 25 abut at the compressed joint 29 to provide,by their contact, a continuous electrical connection from the node 22 tothe second part 28.

FIG. 1 illustrates a sectional side view of the upper half of a gasturbine engine 10. The gas turbine engine 10 comprises, in axial flowseries, an air intake 11, a propulsive fan 12, a compressor arrangement30 comprising an intermediate pressure compressor 13, a high pressurecompressor 14; a combustor 15, a turbine arrangement 32 comprising ahigh pressure turbine 16, an intermediate pressure turbine 17 and a lowpressure turbine 18, an exhaust nozzle 19, an interconnecting shaft 20and a lead 21.

The gas turbine engine 10 operates in a conventional manner so that airentering in the intake 11 is accelerated by the propulsive fan 12 whichproduces two air flows: a first air flow into the intermediate pressurecompressor 13 and a second air flow which provides propulsive thrust.The intermediate pressure compressor 13 compresses air flow directedinto it for delivering air to the high pressure compressor 14 wherefurther compression takes place. The compressed air exhausted from thehigh pressure compressor 14 is directed into the combustor 15 where itis mixed with fuel and the mixture combusted. The resultant hotcombustion products then expand and thereby drive the high, intermediateand low pressure turbines 16, 17, 18 before being exhausted through thenozzle 19 to provide additional propulsive thrust. The high,intermediate and low pressure turbines 16, 17, 18 respectively drive thehigh and intermediate pressure compressors 14, 13 and the propulsive fan12 by suitable interconnecting shafts 20.

FIGS. 2A and 2B illustrate a lead 21 for transmitting an electricalsignal (M) 27, from a node 22 at a first part 24 of a gas turbine engineto a second part 28 of the gas turbine engine. The lead 21 comprises thenode 22, a first interconnect 23, and a second interconnect 25.

The first interconnect 23 is electrically connected to the node 22. Thefirst interconnect 23 is adhered to a first surface 30 and to a thirdabutment surface 33 of the first part 24. The second interconnect 25 isadhered to a second surface 32 and a fourth abutment surface 34 of thesecond part 28. The first surface 30 is, in this example, perpendicularto the third abutment surface 33. The second surface 32 is, in thisexample, perpendicular to the fourth abutment surface 34. A compressedjoint 29 is formed by the compressive contact of the first part 24 andthe second part 28. At the compressed joint 29, the third abutmentsurface 33 and the fourth abutment surface 34 are in abutting contact.Arrows 26 indicate the direction of the compression. The firstinterconnect 23 abuts the second interconnect 25 at the compressed joint29 to provide a continuous electrical connection between the node 22 andthe second interconnect 25 of the second part 28.

In use, the node 22 may be electrically connected to a measurementdevice (not shown in FIG. 2) used for measuring a parameter of the gasturbine engine (temperature for example). The measurement device, inuse, provides the (input measurement) node 22 with an electrical signal(M) 27. The electrical signal (M) 27 is received by the node 22 andprovided to the first interconnect 23. The electrical signal (M) 27 istransmitted through the first interconnect 23 to the second interconnect25 via the electrical contact at the compressed joint 29.

In an alternative embodiment, the electrical signal 27 is transmittedfrom the second interconnect 25 to the first interconnect 23 via theelectrical contact at the compressed joint 29. The electrical signal 27is then provided to the (output) node 22 which may be connected to atransmitter (not shown in FIG. 2) for transmitting the electrical signal27.

It should be appreciated that in the embodiment where the node 22 is aninput measurement node, the second interconnect may terminate at anoutput node or may connect to a third interconnect of a third part viaabutting contact between the second and third interconnects at acompressed joint between the second and third parts.

FIG. 2B illustrates a plan view of the schematic diagram in FIG. 2A.

FIG. 3 illustrates a lead 21 for transmitting an electrical signal (M)27, from a first node 22 at a turbine 42 of a gas turbine engine to asecond node 44 at a compressor stage 40 of the gas turbine engine. Thelead 21 comprises the first node 22, the second node 44, a firstinterconnect 23, and a second interconnect 25.

The first interconnect 23 is electrically connected to the first node22. In use, the first node 22 is connected to a measurement device (notshown in FIG. 3) and is provided with an electrical signal (M) 27. Inthis embodiment, the first interconnect 23 is a first thin filminterconnect 23. The first thin film interconnect 23 is adhered to thesurface 30 of the turbine 42, the surface 47 of a first part 20 a of aninterconnecting shaft 20 and a surface 33 of a first flange 48 of thefirst part 20 a of the interconnecting shaft 20. The first flange 48 islocated within an intermediate stage 46 between the turbine 42 and thecompressor stage 40. The intermediate stage 46 is any stage between theturbine 42 and the compressor stage 40 and may, for example, include thecombustor 15.

The second interconnect 25 is electrically connected to the second node44. In use, the second node 44 is connected to an output device (notshown in FIG. 3). The output device transmits the electrical signal (M)27 to an operator, external to the gas turbine engine. It may be a radiotransmitter. The second interconnect 25 is a second thin filminterconnect 25. The second thin film interconnect 25 is adhered to asurface 32 of the compressor stage 40, to a surface 47 of a second part20 b of the interconnecting shaft 20 and to a surface 34 of a secondflange 49 of the second part 20 b of the interconnecting shaft 20. Thesecond flange 49 is located within the intermediate stage 46.

The first 20 a and second 20 b parts of the interconnecting shaft arejoined at a compressed joint 29. The surface 33 of the first flange 48abuts the surface 34 of the second flange 49. The direction of thecompression is indicated by the arrows 26. A portion of the first thinfilm interconnect 23 on the surface 33 abuts a corresponding portion ofthe second thin film interconnect 25 on the surface 34 at the compressedjoint 29. The first thin film interconnect 23 and the second thin filminterconnect 25 are therefore electrically connected at the joint 29,which provides a continuous electrical connection between the first node22 and the second node 44. Therefore, the electrical signal (M), isreceived at the first node 22, conducted via the first and second thinfilm interconnects 23 and 25 respectively, to the second node 44 whereit is transmitted by an output device to an operator external to the gasturbine engine 10.

The first and second thin film interconnects 23 and 25 respectively maybe adhered to the surfaces of the gas turbine engine 10 by a number ofmethods. The methods for applying thin film are well known within theart of printed circuit boards (PCB) and the like and therefore shall notbe discussed in great detail. The first and second thin filminterconnects 23 and 25 respectively can be adhered to the surfaces ofthe gas turbine engine through painting, lacquering or through theprocess of photolithography.

FIG. 4 illustrates an end view of the first part 20 a of theinterconnecting shaft 20 in FIG. 3. The second part 20 b of theinterconnecting shaft 20 has a corresponding end view. The first part 20a of the interconnecting shaft 20 has an exterior surface 47 having aroughly circular or elliptical cross section. The interconnecting shaft20, in this embodiment, has a cavity 51 that has a roughly circular orelliptical cross section. The first part 20 a of the interconnectingshaft 20 has an inwardly extending first flange 48. The first 48 andsecond 49 flanges have apertures 52 through which a bolt or otherfastening means may be inserted to join the flanges togethercompressively. The first 23 and second 25 thin film interconnects extendradially inwards on the surfaces of the first and second flanges 48 and49 respectively, from the surface 47.

When flanges 48 and 49 are fixed to one another, the asymmetricarrangement of the apertures 52, ensure that only one assemblyconfiguration is possible. This is achieved by spacing the apertures 52at irregular intervals around the circumference of the interconnectingshaft 20. This allows for the accurate alignment of a contact portion ofthe first thin film interconnect 23 with a contact portion of the secondthin film interconnect 25.

Although embodiments of the present invention have been described in thepreceding paragraphs with reference to various examples, it should beappreciated that modifications to the examples given can be made withoutdeparting from the scope of the invention as claimed. For example, thecompressed joint 29 does not necessarily have to be at theinterconnecting shaft, but may be at another part of the gas turbineengine 10. An interconnect may be adhered to any surface and run at anyangle.

Whilst endeavoring in the foregoing specification to draw attention tothose features of the invention believed to be of particular importanceit should be understood that the applicant claims protection of respectof any patentable feature or combination of features hereinbeforereferred to and/or shown in the drawings whether or not particularemphasis has been placed thereon.

1. A lead for transmitting an electrical signal within a gas turbineengine, from a node at a first part of the gas turbine engine having afirst surface to a second part of the gas turbine engine having a secondsurface, wherein the first part and the second part are coupled at acompressed joint, wherein the lead comprises: a node on the firstsurface of the first part; a first interconnect, adhered to the firstsurface of the first part; and a second interconnect, adhered to thesecond surface of the second part, wherein the first interconnect andthe second interconnect abut at the compressed joint to provide, bytheir contact, a continuous electrical connection from the node to thesecond part.
 2. A lead as claimed in claim 1, wherein at least one ofthe first interconnect and the second interconnect is a thin film,having a thickness of less than 0.1 mm.
 3. A lead as claimed in claim 1,wherein at least one of the first interconnect and the secondinterconnect comprises gold or platinum.
 4. A lead as claimed in claim1, wherein the first and second parts are portions of a gas turbineengine spool.
 5. A lead as claimed in claim 1, wherein the first parthas a third abutment surface and the second part has a fourth abutmentsurface, and the first interconnect extends over at least a portion ofthe third abutment surface and the second interconnect extends over atleast a corresponding portion of the fourth abutment surface.
 6. A leadas claimed in claim 5, wherein a portion of the first interconnect isadhered to the third abutment surface and a portion of the secondinterconnect is adhered to the fourth abutment surface.
 7. A lead asclaimed in claim 5, wherein the compressed joint is formed by abuttingcontact between the third abutment surface and the fourth abutmentsurface.
 8. A lead as claimed in claim 7, wherein a portion of the firstinterconnect and a corresponding portion of the second interconnect abutat the compressed joint between the third abutment surface and thefourth abutment surface to provide, by their contact, a continuouselectrical connection from the node to the second part.
 9. A lead asclaimed in claim 1, wherein the first part operates at a temperature inthe range of 200° C. to 800° C.
 10. A lead as claimed in claim 1,wherein the second part operates at a temperature in the range ofambient temperature to 750° C.
 11. (canceled)
 12. (canceled)